This module contains a pure Rust implementation of an H.264 encoder optimized for lossless encoding. It is simple ("less advanced") and uses a small subset of the encoder features in the H.264 specification.
Features and characteristics:
- Pure rust.
- No use of unsafe.
- Lossless encoding of 8 bit and 12 bit monochrome (luminance only 4:0:0) and
color (4:2:0) data.
- Includes an optimized path for luminance-only data in which no chroma data is
saved.
- Encodes using ALL-Intra, also called All-I. Every frame is recorded as an I
(intra) frame (also "keyframe") using PCM encoding.
- Tests decode image with openh264 and
ffmpeg to ensure encoded image is losslessly preserved.
- Can be compiled without using the rust standard library std. In other words,
the no_std attribute is specified. (A global allocator is required.)
Desired but not implemented feature: - Support for other bit-depths and chroma sampling resolutions (e.g. 4:4:4).
Worthy of consideration features: - Support for context-adaptive variable-length coding (CAVLC). - Support for context-adaptive binary arithmetic coding (CABAC).
This was inspired by Ben Mesander's World's Smallest H.264 Encoder.
Run the basic tests with:
cargo test
Full round-trip tests with ffmpeg and openh264 are in the testbench directory
and crate. For those:
cd testbench
cargo test
These tests can export the created streams to .h264 files if the
LESSAVC_SAVE_TEST_H264 environment variable is set. (To view the location
where the .h264 files are saved, run the tests with
cargo test -- --nocapture.) To convert these to .mp4:
```
set -o errexit
FILES="./*.h264" for f in $FILES do echo "Processing $f file..." ffmpeg -i $f -vcodec copy $f.mp4 # ffmpeg -i $f $f.png done ```
Benchmarks are in the testbench directory and crate:
``` cd testbench cargo bench
RUSTFLAGS='-C target-cpu=native' cargo bench ```
Copyright 2022-2023 Andrew D. Straw.
Licensed under the Apache License, Version 2.0